Co-director, Harvard Stem Cell Institute
Why he matters: For a while it looked as though the South Koreans were winning the race to find real-world uses for human stem cells. But when their research program melted down in a data-faking scandal, Melton emerged as the prime mover in a field that could someday offer treatments for everything from cancer to diabetes to Parkinson's disease.
When the White House cut funding for experiments based on stem cells taken from human embryos, Melton used private donations to create 30 embryonic stem-cell lines and distribute them to labs around the world. His cells, and scientists he trained, are now driving the research agenda in this promising field.